Two-system protocol conversion transceiver repeater

Abstract

A system and method are disclosed for bidirectionally coupling a first satellite communication system to a second satellite communication system, wherein the first and second systems operate with different protocols. In a presently preferred embodiment of this invention the first system uses a spread spectrum (SS), code division multiple access (CDMA) technique wherein the satellites serve as simple `bent pipe` repeaters for relaying communications between a user and a gateway. The second satellite communication system may be any other type of system having at least one characteristic that precludes direct communication between the first and the second systems. In an exemplary embodiment the second system uses a time division multiple access (TDMA) technique, and furthermore enables direct satellite-to-satellite communication links. A ground-based protocol conversion unit (70) is positioned for receiving a communication from a satellite of either the first or the second system, and includes circuitry for converting the transmission into a transmission that is suitable for transmission into the other system.

What is claimed is: 
     
       1. A communication repeater unit, comprising: a first transceiver for bidirectionally communicating with at least one first satellite of a first satellite-based communication system;   a second transceiver for bidirectionally communicating with at least one second satellite of a second satellite-based communication system;   wherein said first satellite-based communication system employs a first protocol, wherein said second satellite-based communication system employs a second protocol, wherein the first protocol is different than the second protocol; and wherein said repeater unit further comprises,   a protocol converter that is bidirectionally coupled to said first transceiver and to said second transceiver for receiving a transmission from one of said satellite-based communication systems, for converting the received transmission to the protocol employed by the other satellite-based communication system, and for transmitting a protocol-converted transmission to the other satellite-based communication system; and wherein   said first and second transceivers are both located at a terrestrial location.   
     
     
       2. A communication repeater unit as set forth in claim 1 and further comprising a data base of authorized users, and wherein said protocol converter converts a received transmission only if the received transmission is originated by a user that is recorded in the data base of authorized users. 
     
     
       3. A communication repeater unit as set forth in claim 1, wherein said first satellite-based communication system employs a spread spectrum, code division multiple access-based protocol, and wherein said second satellite-based communication system employs a time division, multiple access-based protocol. 
     
     
       4. A communication system as set forth in claim 3, wherein said at least one first satellite of said first satellite-based communication system is capable of direct communication only with terrestrial transceivers, including said first transceiver, and wherein said at least one second satellite of said second satellite-based communication system is capable of direct communication with terrestrial transceivers, including said second transceiver, and also with at least one other satellite of said second satellite-based communication system. 
     
     
       5. A hybrid communication system, comprising: a first satellite-based communication system including at least one first satellite;   a second satellite-based communication system including at least one second satellite;   wherein said first satellite-based communication system employs a first protocol, wherein said second satellite-based communication system employs a second protocol, wherein the first protocol is different than the second protocol; and wherein said hybrid communication system further comprises at least one protocol conversion unit that includes,   a first transceiver for bidirectionally communicating with said at least one first satellite of said first satellite-based communication system;   a second transceiver for bidirectionally communicating with said at least one second satellite of said second satellite-based communication system; and   a protocol converter that is bidirectionally coupled to said first transceiver and to said second transceiver for receiving a transmission from one of said satellite-based communication systems, for converting the received transmission to the protocol employed by the other satellite-based communication system, and for transmitting a protocol-converted transmission to the other satellite-based communication system; and wherein   said first and second transceivers are both located at a terrestrial location.   
     
     
       6. A hybrid communication system as set forth in claim 5 wherein said at least one first satellite is a low earth orbit satellite comprising means for receiving a communication uplink feeder link from at least one ground station and means for transmitting the received communication feeder link to a plurality of terrestrially located terminals that are located within a downlink coverage area associated with said first satellite, and wherein said at least one ground station comprises means for transmitting said communication feeder link to said at least one first satellite and further comprises means for coupling said communication feeder link to a terrestrially located communication system. 
     
     
       7. A hybrid communication system as set forth in claim 5 wherein said protocol converter further comprises a data base of authorized users, and wherein said protocol converter converts a received transmission only if the received transmission is originated by a user that is recorded in the data base of authorized users. 
     
     
       8. A hybrid communication system as set forth in claim 5, wherein said first satellite-based communication system employs a spread spectrum, code division multiple access-based protocol, and wherein said second satellite-based communication system employs a time division, multiple access-based protocol. 
     
     
       9. A hybrid communication system as set forth in claim 8 wherein said at least one first satellite of said first satellite-based communication system is capable of direct communication only with terrestrial transceivers, including said first transceiver, and wherein said at least one second satellite of said second satellite-based communication system is capable of direct communication with terrestrial transceivers, including said second transceiver, and also with at least one other satellite of said second satellite-based communication system. 
     
     
       10. A method for communicating from one user terminal to another user terminal, comprising the steps of: originating a communication at a first terminal;   relaying the communication through a ground station to at least one satellite of a first satellite-based communication system, the first satellite-based communication system operating in accordance with a first protocol;   repeating the communication with the at least one first satellite;   receiving the repeated communication with a terrestrially located receiver;   converting the received, repeated communication into a communication with a second protocol that is associated with a second satellite-based communication system;   transmitting the converted communication into the second satellite-based communication system with a terrestrially located transmitter;   receiving the transmitted converted communication with at least one second satellite of the second satellite-based communication system; and   delivering the converted communication to a second terminal.   
     
     
       11. A method as set forth in claim 10 wherein the step of delivering includes a step of relaying the converted communication from the at least one second satellite to at least one further satellite of the second satellite-based communication system. 
     
     
       12. A method as set forth in claim 10 wherein the step of converting includes an initial step of determining if the communication was initiated by a user that is recorded in a data base of authorized users. 
     
     
       13. A method as set forth in claim 10, wherein the first satellite-based communication system employs a spread spectrum, code division multiple access-based protocol, and wherein the second satellite-based communication system employs a time division, multiple access-based protocol. 
     
     
       14. A method as set forth in claim 10, wherein the step of converting converts at least one of access type, modulation type, frequency plan, bit rate, signalling format, error protection technique, power level control, voice coding technique, voice coding rate, access and paging format, call set-up format, and handover technique. 
     
     
       15. A method as set forth in claim 10, wherein the first satellite-based communication system employs a first spread spectrum, code division multiple access-based protocol, and wherein the second satellite-based communication system employs a second spread spectrum, code division multiple access-based protocol that differs from the first spread spectrum, code division multiple access-based protocol. 
     
     
       16. A method as set forth in claim 10, wherein the communication that is converted from the first protocol to the second protocol is a pager communication. 
     
     
       17. A communication system, comprising: a first satellite-based communication system including at least one first satellite;   a second satellite-based communication system including at least one second satellite;   wherein said first satellite-based communication system employs a first protocol for communicating a pager message, wherein said second satellite-based communication system employs a second protocol for communicating a pager message, wherein the first protocol is different than the second protocol; and wherein said hybrid communication system further comprises at least one protocol conversion unit that includes,   a first transceiver for bidirectionally communicating with said at least one first satellite of said first satellite-based communication system;   a second transceiver for bidirectionally communicating with said at least one second satellite of said second satellite-based communication system; and   a protocol converter that is bidirectionally coupled to said first transceiver and to said second transceiver for receiving a pager communication transmission from one of said satellite-based communication systems, for converting the received pager transmission to the protocol employed by the other satellite-based communication system, and for transmitting a protocol-converted pager communication transmission to the other satellite-based communication system; wherein   said first and second transceivers are both located at a terrestrial location.   
     
     
       18. A communication system as set forth in claim 17 wherein said at least one first satellite is a low earth orbit satellite comprising means for receiving a communication uplink feeder link from at least one ground station and means for transmitting the received communication feeder link to a plurality of terrestrially located terminals that are located within a downlink coverage area associated with said first satellite, and wherein said at least one ground station comprises means for transmitting said communication feeder link to said at least one first satellite and further comprises means for coupling said communication feeder link to a terrestrially located communication system. 
     
     
       19. A communication system as set forth in claim 17 wherein said protocol converter further comprises a data base of authorized users, and wherein said protocol converter converts a received pager communication transmission only if the received pager communication transmission is associated with a user that is recorded in the data base of authorized users. 
     
     
       20. A communication system as set forth in claim 17, wherein said first satellite-based communication system employs a spread spectrum, code division multiple access-based protocol, and wherein said second satellite-based communication system employs a time division, multiple access-based protocol. 
     
     
       21. A communication system as set forth in claim 17, wherein said at least one first satellite of said first satellite-based communication system is capable of direct communication only with terrestrial transceivers, including said first transceiver, and wherein said at least one second satellite of said second satellite-based communication system is capable of direct communication with terrestrial transceivers, including said second transceiver, and also with at least one other satellite of said second satellite-based communication system. 
     
     
       22. A communication method, comprising the steps of: originating a communication in a first satellite communication system that operates in accordance with a first air interface specification;   transmitting the communication from a satellite of the first satellite communication system to a ground station;   receiving the communication at the ground station;   converting the received communication from the first air interface specification to a second air interface specification used by a second satellite communication system;   transmitting the converted communication from the ground station to a satellite of the second satellite communication system;   receiving the converted communication with the satellite of the second satellite communication system; and   delivering the converted communication to a ground terminal via the satellite of the second satellite communication system.   
     
     
       23. A method as set forth in claim 22, wherein the step of delivering includes a step of relaying the converted communication from the satellite of the second satellite communication system through at least one further satellite of the second satellite communication system.